Beware of Cats

An American ecologist has publish a provocative research paper that suggests a cat parasite has affected the personalities of roughly half the world’s population.

The parasite, Toxoplasma gondii, is thought to have been transmitted to approx half the people on the planet, and research has shown it affects human personalities in different ways.

Women who are infected with the parasite tend to be warm, outgoing and attentive to others, while men tend to be less intelligent and boring. But both men and women who are infected are more prone to feeling guilty and insecure.

Other research has linked the parasite to schizophrenia. In an adult, the symptoms are often likened to flu, but can be much more serious in young children.

Oxford University researchers believe high levels of the parasite leads to hyperactivity and lower IQs in children.

Building on research done by scientists in the Czech Republic, Kevin Lafferty, a parasite ecologist with the U.S. Geological Survey at the University of California at Santa Barbara, took an in depth look at areas of the globe where infection levels are quite high, or quite low.

In Brazil, for example, two out of three women of child-bearing age are infected, whereas in the United States the number is only one out of eight.

Lafferty argues in a research paper published Aug. 2 in the Proceedings of the Royal Society, Biology, that aggregate personality types, or the overall personality of a culture, fits neatly with the effects that parasite produces in individuals.

Looking at the results, Lafferty theorized:

“Can a common cat parasite account for part — even if only a very small part — of the cultural differences seen around the world?

“It’s kind of way out in left field, I think it’s the strangest thing I’ve ever worked on.”

“Toxoplasma, is “frighteningly amazing.”

It can change the personality of a rat so much that the rat almost surrenders itself to a cat, just as the parasite wanted.

The parasite’s eggs are shed in a cat’s feces. When the rat eats the feces, it becomes infected. Once infected the rat begins a dramatic personality change, making the rat more adventurous and more likely to venture into areas where there are cats. The cat eats the rat, and the parasite completes its life cycle.

“That manipulation of the local ecology is not unusual for a parasite,” Lafferty says.

“This is something that many parasites do, many manipulate hosts’ behavior… “So it wasn’t much of a jump to the next question: “We have a parasite in our brain that is trying to get transmitted to a cat, this changes an individual’s personality… “So if enough of us are infected and undergo personality changes, is it possible that our culture could be altered as a whole?”

Lafferty admits anthropologists are not likely to embrace his theory:

“Anthropologists are not in agreement that you can drive a culture from the bottom up,”

But he sees that happening throughout the parasitic world, involving many types of animals, so why is it inconceivable that it could also be happening among humans?

Nevertheless, Lafferty says cat lovers need not get rid of their cats. The chances are not great that a modern cat, kept on a diet of safe cat food and not left to feed off rats, will transmit the parasite to humans. It’s possible, but not likely:

“This isn’t about trying to freak cat owners out, simply having a cat as a pet doesn’t mean you’re going to get infected, for sure.”